7075 Al-alloy suffered often from corrosion damages during service in coastal area environments, due to seawater splash or salt atmosphere corrosion. Therefore, for the problem of high strength but poor corrosion resistance of 7075 Al-alloy, a cyclic strengthening (CS) process at ambient temperature is adopted to improve its strength and corrosion resistance. Compared with the traditional peak aging T6, the cyclic strengthening treated 7075 Al-alloy shows better corrosion resistance with higher free-corrosion potential and higher impedance value in electrochemical test. In NaCl solution, the intergranular corrosion depth of the T6 treated alloy was 58 μm, while that of the CS treated one was only 15 μm. The corrosion pits and corrosion microcracks formed for the CS alloy are smaller than that of the T6 ones in salt spray corrosion test. The corrosion products of both T6 and CS alloy contain Zn(OH)₂ and ZnCl₂, the formation of which is due to the electrochemical reaction between the η′(MgZn₂) phase at the grain boundaries of the T6 alloy, and the clusters of atoms in the CS alloy and the Al-matrix, respectively. After the CS process, a large number of dislocations and clusters of atoms are generated within the 7075 Al-alloy, which hinders the dislocation movement and increases the free-corrosion potential, thereby improving the strength and corrosion resistance of the 7075 Al-alloy.